, too. >>> the sense of urgency is growing by the hour. along the israel-gaza border. hamas militants are hammering targets deep inside enemy territory as we speak, infli inflicting damage, casualties and sparking panic. air sirens wailed for a third straight day in tel aviv after hamas fired a rocket toward the sea side city. the rocket was intercepted. israeli soldiers backed up in armored vehicles are going to the border raising the specter of a possible ground war. all 30,000 troops mobilized and 70,000 more on the way. as the situation he is escalate does the death toll. now our senior international correspondent has been in the middle of all the action in gaza city. sarah, thanks for joining us. what's happening there right now? >> reporter: thank you, gary. yeah, we can hear right now drones over gaza. and that sound, it sounds very much like a lawnmower. it's been going on for hours and hours and hours. we know a lot about drones. israel uses them quite often. they can stay up in the air. they're unmanned, obviously, for more than 20 hours depending on the payload. so if they'